The present invention relates to a high frequency incision tool for endoscope for use through a treatment tool guide lumen of an endoscope.
High frequency incision tools for endoscope are available in various shapes depending on applications. As an example used for separation of mucous membranes, JP-A-2003-299667 discloses an incision tool including scissors-like electrodes in which a pair of electrode blades disposed in parallel and oriented forward at the front position of a sheath can be remotely opened and closed from the rear end of the sheath.
However, the above-mentioned related high frequency incision tool for endoscope has a problem that at the beginning of use, when the front end of the incision tool protrudes from the treatment tool guide lumen of the endoscope into the body, the tip of the thin electrode blade may violently press and damage the surface the mucous membrane, or even puncture the mucous membrane at worst. Although the use of cup-like electrode blades of bawl-shaped biopsy forceps eliminates such a problem, such a cup of the bawl-like electrode blade blocks the direct endoscopic view of part of the portion to be incised during high-frequency incision, compromising patient safety.
Furthermore, in a separation procedure of a mucous membrane from the underlying muscle layer, the incision is carried out while the electrode blades are inserted between the superficial mucous membrane and the muscle layer and a high-frequency current is applied. However, with the related high-frequency incision tool for endoscope, the electrode blades may touch a portion that is not intended to be incised, resulting in possible burning of the mucous membrane and muscle layer. Moreover, before applying the high-frequency current, it is required to create a gap between the superficial mucous membrane and the muscle layer in a mechanical manner. Although thin electrode blades may be used for that purpose, it may only be pushed in the mucous membrane but cannot create a gap between the mucous membrane and the muscle layer as desired.